Dye-sensitized solar cells (DSCs) have been investigated extensively as potential alternatives to conventional silicon solar cells, by using wide-bandgap nanocrystalline TiO2 sensitized with sensitizing dyes. By using ruthenium complexes through novel molecular design, SHARP [Jpn. J. Appl. Phys., 45, (2006) L638.] and our group [J. Am. Chem. Soc., 127 (2005) 16835.] reported over-11%-efficiency DSCs against AM1.5 (AM: air mass) simulated solar light of 100 mWcm–2 (1 sun). However, Ru dyes are not suitable to cost-effective environmental-friendly photovoltaic systems, because the Ru atom is an expensive heavy metal. Therefore, investigation of an organic-dye-sensitized solar cell is very important. In 2006, we reported that a metal-free organic dye (indoline dye: D149) [Adv. Mater., 18 (2006) 1202.] reached 9.03% power-conversion efficiency, which has been the best result as an organic-dye-sensitized solar cell. In order to enhance the photoenergy-conversion efficiency, it is necessary to control the aggregation between the dyes. For example, D149 shows J-aggregation on nanocrystalline-TiO2 electrodes. And each Ru dye (black dye and N719) shows the best record with using chenodeoxycaulic acid (CDCA), which worked as an anti-aggregation reagent. For controlling the aggregation, in this paper, the D149 is remodeled by introduction of bulk substitutes of octhyl chain: D205. By using CDCA, specially, the DSC with D205 exhibited high values of open-circuit photovoltage over 700 mV, resulting in 9.52% power-conversion efficiency under 1-sun irradiation(Fig.). This is the best record published as an organic-dye-sensitized solar cell so far.